Ion implantation is a process of depositing chemical species into a substrate by direct bombardment of the substrate with energized ions. In semiconductor manufacturing, ion implanters are used primarily for doping processes that alter the type and level of conductivity of target materials. A precise doping profile in an integrated circuit (IC) substrate and its thin-film structure is often crucial for proper IC performance. To achieve a desired doping profile, one or more ion species may be implanted in different doses and at different energy levels.
To form devices on a semiconductor wafer, it is usually necessary to implant impurities at different depths of the semiconductor wafer. The energy of impurities in an ion beam directed toward the semiconductor wafer is determinative of the depth to which the impurities penetrate into the semiconductor wafer. As devices are reduced in size and increased in speed, it has become desirable to use very low energy ion beams to form, for example, shallow transistor junctions in the semiconductor wafer.
At the same time, high energy ion implantation may help minimize production costs because high energy ion implantation does not require some conventional processes, such as, but not limited to, the masking of a semiconductor wafer, to be performed. Also, semiconductor devices manufactured through the use of high energy ion implantation may exhibit relatively low levels of junction leakage and improved latch-up characteristics. Thus, the production yield may be high with respect to an ion implantation process carried out by high energy ion implantation. Therefore, high energy ion implantation may be widely used for implanting ions in semiconductor device manufacturing processes.
FIG. 1 depicts a prior art ion implanter system 100. The ion implanter system 100 may comprise an ion source 102 and a complex series of components through which an ion beam 10 passes. The series of components may include, for example, an extraction manipulator 104, a filter magnet 106, an acceleration or deceleration column 108, an analyzer magnet 110, a rotating mass slit 112, a scanner 114, and a corrector magnet 116. The ion source 102, the extraction manipulator 104, and the filter magnet 106 may be housed in a terminal 118. Much like a series of optical lenses that manipulate a light beam, the ion implanter components can filter and focus the ion beam 10 before steering it towards an end station 120.
The terminal 118 is a critical component to the ion implanter system 100. In certain instances, an acceleration voltage for ion beams may be above 600 kV. As a result, during an ion beam acceleration mode, certain components of the ion implantation system 100, including, for example, the terminal 118, may be at a high voltage, while other components may be at a low voltage or ground. In other modes of operation, such as a deceleration mode, it may be necessary to connect a deceleration power supply to the ion source 102. Selectively providing an electrical connection to ground can be challenging, as the terminal 118 and other components may be physically separated from ground. Further, conductive material (e.g. a metal wire or switch) between the terminal 118 and ground may cause arcing when the system 100 is operated in a high voltage acceleration mode. Moreover, if there are components between the terminal 118 and ground (e.g., a ceramic insulator), there may be a concern for tracking distance. In the present disclosure, tracking distance may be referred to as the distance from one voltage potential to another voltage potential along a surface path of a component between two voltage potentials. A design rule may be followed to limit the tracking distance (e.g., 10 kV/inch in air).
In view of the foregoing, it may be understood that there are significant problems and shortcomings associated with current technologies in making high voltage connections for ion implanters.